Iran's interior minister says the country's presidential election will likely head to a runoff with no candidate winning more than 50 percent of Friday's vote.
Former President Ali Akbar Hashemi Rafsanjani and pro-reform candidate Mostafa Moin were considered the front-runners going into the voting.
Turnout was officially reportedly to be high, and authorities kept the polls open four hours past closing time.
The government had called for a large turnout to counter calls for a boycott by some in the opposition, who said voting legitimizes a system where unelected clerics hold the true power.
VOA's Gary Thomas reported from Tehran that seven candidates were permitted to compete.
Outside the Hossein-e-Ershad Mosque complex in central Tehran, lively debates sprung up between political partisans.
Inside, people lined up to vote in what could turn out to be the tightest presidential election in post-Islamic revolution Iran. Officials extended the voting time three hours past the 7:00 p.m. deadline.
Former President Ali Akbar Hashemi Rafsanjani went into Friday's vote as a narrow favorite. But supporters of reform candidate Mostafa Moin believed their man could pull off an upset victory, as outgoing President Mohammad Khatami did in 1997. Ex-national police chief Mohammad Baqer Qalibaf is Mr. Rafsanajani's other main challenger. Hundreds of other potential candidates, mainly reformists and women, were disqualified by the Guardian Council, an unelected body of hard-line mullahs.
The candidates are battling apathy and cynicism, particularly among reformers disappointed at how hardliners blocked Mr. Khatami's efforts at democratic reform. Some students called for a boycott of the vote.
Casting his own ballot at the Interior Ministry, the outgoing president said the path to democracy is long and difficult, but that should not discourage people from voting.
At the Hossein-e-Ershad Mosque, there was much talk of President Bush's criticism of the Iranian election. On Thursday, Mr. Bush said the Iranian government is repressive, and the election ignores the basic requirements of democracy.
Behnaz Keyhan Khadiv, casting her vote along with her daughter, Maryam Mohammadzadeh, challenged Mr. Bush's remarks, saying the election is democratic. "If this is not - this scene that you are here, you can see all people are here - if this is not democracy, then where is democracy?"
One Iranian voter said Mr. Bush's remarks may have actually increased voter turnout.
Early conclusive results are not expected to be known until late Saturday. If no one gets over 50 percent, a runoff will be held June 24, between the top two vote-getters.